In the past, Patent Document 1 disclosed a cooling device for a hybrid electric vehicle that includes an engine cooling system of which the target coolant temperature is high, a motor cooling system of which the target coolant temperature is medium, and a battery cooling system of which the target coolant temperature is low.
In this related art, a water pump is disposed in each of the engine cooling system, the motor cooling system, and the battery cooling system, an engine is disposed in the engine cooling system, and an electric motor and a heat storage device are disposed in the motor cooling system.
Further, in this related art, the engine cooling system and the motor cooling system are connected to each other through a coolant pipe and a three-way valve, and the engine cooling system and the motor cooling system can be disconnected from each other or connected to each other.
For example, a motor generator, an inverter, a battery, an EGR cooler, an intake air cooler, and the like are present as heat exchange devices, which are mounted on the vehicle, in addition to the engine, the electric motor, and the heat storage device. Required control temperatures of these heat exchange devices are different from each other.